Two-fluid galvanic cell.



J. HESSELN. TWO FLUID GALVANIG CELL.

APPLICATION FILED NOV.23, 1910.

Patented July 16, 1912.

COLUMBIA PLANcmRM-n NJ-,WASNINGTON, 0.1:

WILI-IELM JOHANN HESSELN, OF ARNI-IEIM, NETHERLANDS.

TWO-FLUID GALVANIC CELL.

Specification of Letters Patent.

Patented July 16,1912.

-Application filed November 23, 1910. Serial No. 593,916.

To all whom it may concern:

Be it known that I, IVILHELM JOHANN HESSELN, a citizen of the Kingdom ofthe Netherlands, residing at Arnheim, Netherlands, have invented certainnew and useful Improvements in Two-Fluid Galvanic Cells, of which thefollowing is a specification.

This invention relates to two-fluid galvanic cells having a carbondiaphragm serving also as an electrode, and it has for its ob ect torender the diflusion between the two liquid electrolytes automaticallyproportionate to the Varying requirement of the cell, that is to thevarying consumption of electric current, and to stop the diffusion asfar as possible while the cell is at rest. This object is effectedaccording to this invention by utilizing the warm gases and vaporsgenerated by the electro-chemical action to pro.- duce pressure actingupon the liquid electrolyte. This utilization of the gases and vaporsmay be effected alone or in conjunction with capillary material lyingagainst the sides of the diaphragm or situated within the insertions.

TWO Ways of carrying out this invention are illustrated by way ofexample in the accompanying drawings in which:

Figure l is a vertical section of a cell embodying the utilization ofpressure and vacuum only; and F 1g. 2 1s a similar view of a cell inwhich, capillary action is employed in addition to the utilization ofpressure and vacuum for regulating the diflusion of theelectrolyticliquid.

In both figures, a is the outer vessel of the cell, Z) the carbondiaphragm (serving also as an electrode), 0 a metal electrode oi: zinc,iron, alumlnlum or other suitable metal, and

(Z is a lid with a stopper 6.

As shown in Fig. 1, f is a tubular or other hollow insertion, preferablyof glass, vulcanite, celluloid, earthenware, but which may also be ofcarbon or the like; it is arranged on the underside of the lid and dipsto a greater or less depth into the electrolyte. The warm gases whichare generated on the discharge of current, mostly along the sides I ofthe carbon electrode Z), rise between the Now since this pressure causesthe inner level of the liquid to be higher than the level of the outerliquid surrounding the metal electrode, the pressure due to this greaterhead of liquid will cause the diffusion of the liquid contained withinthe carbon electrode, to be more or less accelerated and proportionateto the varying requirements. As soon as the consumption of currentceases in whole or in part, the generation of gas and heat will alsocease in whole or in part, and thereby cause the raised column of liquidin the insertion f to sink again. Further, owing to the cooling of thegases and the condensation of the vapors, a certain vacu- 'um will beproduced between the carbon and the insertion f, which will enable theliquid (or portions thereof) that surrounds the metal electrode and nowstands at a higher level, to pass back to a greater or less depth intothe carbon and thus prevent the liquid contained in the carbon fromditl'using or passing out from the latter while the cell is at rest.

If the aforesaid pressure action should produce a too great pressure inthe carbon. electrode, this pressure will be relieved by the escape ofgases through the stopper 6. In such a case however the gases must firstpass through the liquid by which they are partly absorbed.

By arranging the tubular or other hollow insertion f to dip to a greateror less depth in the liquid, or by making it of a greater or smallerdiameter or other dimensions, the

level to which the liquid is raised by the one piece, the bottom ofsuch. vessel is ren-' dered as usual impervious by means of paraliin,varnish, or the like, except in those cases where a metal electrode issituated in front of the bottom of such vessel.

A layer Z of suitable porous material. such as asbestos, glass wool,coarsely powdered glass or carbon, or mealy substance, is rammed inbetween the insertion f and the sides of the diaphragm up to say, theheight of the normal level is of the liquid. Owing to the perviousnessor perforations of the insertion f, thisrammed porous layer read -ilybecomes saturated with liquid and thus.

offers a certain resistance to the passage of the liquid through thecarbon diaphragm. This resistance is only overcome by the action of thecurrent and the chemical processes and pressure actions consequentthereon, whereby it causes the amount of liquid which is necessary atthe time to pass through or difluse.

During the operation of the cell, the generated gases and vapors rise,fill the cavity of that portion of the air-tight insertion f which isimpervious from say the level 9 upward, and they then exert upon theelectrolyte a pressure which is proportionate to the consumption of thecurrent and which accelerates the difiusion or passage of the liquidthrough the carbon 5 When the electrolyte has been depressed to thelevel 9 where the pervious structure or the perforations of theinsertion f begin, the gases are able to escape at k through the layersaturated with liquid, or through the 0 holes 1' in the lid.

It is impossible for the gases and vapors A to escape at g or at 70,without filling the upper cavity of the insertion f, and there foreexerting their pressure effects therein, because the capillary action ofthe saturated layer oflers a very great resistance to the rise of theliquid in it, and a consequent premature escape at g or is, if in factit does not render such rise impossible. The gases 40 and vapors aretherefore compelled to rise in the liquid in the insertion f, and to actfrom above in the hereinbefore described manner before they can escape.This efiect is further aided by the circumstance that the portion ofporous material situated between 9 and is, continually absorbs freshliquid from below so that the liquid is forced by the escaping gases uppast the level 70, whereby the opening 9 for the escape of the gas underexcessive pressure'is always kept covered. The capillary action l of theporous layer has also the advantage that the porous material will remainsaturated throughout its height almost so long as there is still anyelectrolyte in the insertion f. In this manner the walls of thediaphragm will remain covered from top to bottom with liquid until theelectrolyte contained in the cell is almost entirely consumed, whereby auniform current effect is produced also in the vertical direction.

7 When the cell is at rest, the pressure actions cease again, so thatowing to the cooling and consequently produced vacuum, the liquid (orportions thereof) which surrounds the diaphragm.

im ges metal electrode and has been forced upward owing to thecapillarity of the porous material, the replacing of the usedelectrolyte by fresh liquid is rather more difficult.

In the construction shown in Fig. l, the insertion f may likewise becarried down to the bottom and be made pervious or perforated below thenormal level of the liquid; it may also be provided independently withporous material for the purpose of utilizing this porous materialsaturated with liquid to cause the contained electrolyte to pass as muchas possible through the carbon diaphragm in the manner described withreference to Fig. 2. It is immaterial whether the diaphragm of carbon orgraphite is of round, polyg nal or other shape, and whether the metalelectrode with its appurtenant liquid electrolyte is situated within orwithout the carbon electrode, and also whether in the case of largecarbon diaphragm vessels, there are a number of the insertions In thecase of electrolytes which give off little or scarcely any gas or heat,it is advisable to add to them a small percentage of 7 nitric acid,hydrochloric acid or the like to promote the generation of gas, andconse quently of pressure.

A special advantage of utilizing the hereinbefore described pressureactions and capillary effects and the resulting automatic regulation ofthe diffusion, consists in that not only can weak, strong and evenconcentrated mixtures of liquids be employed with equally good results,but also the well known mixtures of sulfuric acid, nitric acid,hydrochloric acid and the like, with theaddition 5 of chromates,bichromates, permanganates, oxidizing nitrates, chromic acid and thelike.

Existing constructions of cells in which the electrolytes remain at restand work solely with the ordinary diminution of diffusion that increasesin working, the employment of the above mentioned electrolyte mixturesis possible with some success only within certain concentration limitsof the acids and with the use of small quantities of oxidizing agents,because otherwise the added oxidizing salts and their compounds with theacids are very apt to choke the pores of the diaphragm and hinder thecurrent effects too much. In cells constructed according to thisinvention those drawbacks occur either not at all or not to anydisturbing extent, because the electro lytes are maintained in continualmovement by the pressure actions and are, as it were, pushed to-and-froso that no choking of the diaphragm can occur. Even with the use ofnitric acid alone, which as is well known, difiuses through carbon withmore difficulty than sulfuric acid, it is possible to obtain goodresults with any desired degree of concentration, owing to the saidpressure actions.

What I claim is:

1. In a two-fluid galvanic cell having a carbon diaphragm and electrode,a hollow insertion in the carbon diaphragm space dipping into the liquidof the cell when in operation so as to form a liquid-sealed cavitywithin the cell, allowing accumulation of gases and vapors generatedduring the operation of the cell for the purpose of influencing thedifliusion of liquid through the diaphragm.

2. In a two-fluid galvanic cell having a carbon diaphragm and electrode,a tubular insertion inside the carbon diaphragm space dipping into theliquid within said space during the operation of the cell, and a metalelect-rode outside said carbon diaphragm space.

3. In a two-fluid galvanic cell having a carbon diaphragm and electrode,a tubular insertion in the carbon diaphragm space dipping into theliquid within said space carbon diaphragm and electrode, a hollowinsertion in the carbon diaphragm space, dipping into the liquid withinsaid space during operative condition of the cell so as to form aliquid-sealed cavity therein, and absorbing material between said hollowinsertion and diaphragm.

6. In a two-fluid galvanic cell having a carbon diaphragm and electrode,a tubular insertion in the carbon diaphragm space reaching down to thebottom of said space and permeable to liquid in its lower part be lowthe point which normally occupies the level of the liquid duringoperation, and absorbing material between said tubular insertion andsaid diaphragm.

In testimony whereof, I afliX my signature in presence of two witnesses.

WVILHELM J OHANN I-IESSELN.

Witnesses HENRY HASPER, WVOLDEMAR I-IAUPT.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Iatents,

' Washington, D. G.

